Salisbury screen with lossy nonconducting materials: Way to increase spectral selectivity of absorption

• Published in: Thin solid films Vol. 751; p. 139232
• Main Authors: Medvedev, V.V., Novikova, N.N., Zoethout, E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2022
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2022.139232

•A modified Salisbury screen design using lossy nonconducting layers is proposed.•Total absorption conditions are derived for the modified Salisbury screen.•Proof-of-principle Ge/Si/Al structures prepared.•Narrow-band absorption in the near-infrared range demonstrated. We present a modified Salisbury screen design in which the thin absorbing metal layer is replaced with a layer of nonconducting lossy material. The conditions for total absorption in such a structure are explained using a simplified analytical model and rigorous numerical calculations. For the proof-of-principle experiments, germanium/silicon bilayers deposited on aluminium substrates are designed and manufactured. The structures demonstrate nearly perfect absorption in the near-IR spectral range. Compared to conventional Salisbury screens, a lossy semiconductor top layer exhibits increased spectral selectivity of absorption. The wavelength of nearly perfect absorption remains tunable by optimizing the thicknesses of the lossy and transparent layers.